Printed circuit boards (PCBs) are widely known in the art and are used for forming a wide variety of types of electrical devices. Printed circuit boards typically consist of a number of layers of copper conductors which are interconnected by metallized holes. The metallized holes can be in different forms, such as microvias, buried vias, blind vias and through-holes. In the typical cases, the hole has a single function: the plating in the hole connects all copper layers exposed in the hole to each other, or the hole is used for component insertion.
Vias have also served dual purposes such as providing layer-to-layer interconnection and through-hole component mounts. The growth of surface mount component technology however, has reduced the need to utilize holes for through-hole component mount and has resulted in the via primarily providing layer-to-layer interconnection, i.e., a via hole.
There has, however, been a trend to provide PCBs having increasingly higher circuit density and higher circuit speed. Many of these designs have a few dense high Input/Output components grouped together. Thus, many PCB will have a very dense area around the high Input/Output components, while the remainder of the PCB is often of lower density. These very dense areas cause an increased layer count in the PCB resulting in an increased cost of the PCB.
To help meet the demand for increased circuit density, it has been proposed to provide more than one independent signal path or connection in a single via. However, there are limitations with vias. The surface area of vias are too large for the new generations of components and pushing the limits down in hole size cause yield issues in the drilling, cleaning, and plating of the vias. Thus, a need exists for a structure with a reduced surface area having electrically isolated segments. It is to such an improved method of producing PCBs that the present invention is directed.